Andrew's git / gitweb.git / grep.c
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grep.con commit fast-import: Improve robustness when D->F changes provided in wrong order (253fb5f)
   1#include "cache.h"
   2#include "grep.h"
   3#include "userdiff.h"
   4#include "xdiff-interface.h"
   5
   6void append_header_grep_pattern(struct grep_opt *opt, enum grep_header_field field, const char *pat)
   7{
   8        struct grep_pat *p = xcalloc(1, sizeof(*p));
   9        p->pattern = pat;
  10        p->origin = "header";
  11        p->no = 0;
  12        p->token = GREP_PATTERN_HEAD;
  13        p->field = field;
  14        *opt->header_tail = p;
  15        opt->header_tail = &p->next;
  16        p->next = NULL;
  17}
  18
  19void append_grep_pattern(struct grep_opt *opt, const char *pat,
  20                         const char *origin, int no, enum grep_pat_token t)
  21{
  22        struct grep_pat *p = xcalloc(1, sizeof(*p));
  23        p->pattern = pat;
  24        p->origin = origin;
  25        p->no = no;
  26        p->token = t;
  27        *opt->pattern_tail = p;
  28        opt->pattern_tail = &p->next;
  29        p->next = NULL;
  30}
  31
  32struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
  33{
  34        struct grep_pat *pat;
  35        struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
  36        *ret = *opt;
  37
  38        ret->pattern_list = NULL;
  39        ret->pattern_tail = &ret->pattern_list;
  40
  41        for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
  42        {
  43                if(pat->token == GREP_PATTERN_HEAD)
  44                        append_header_grep_pattern(ret, pat->field,
  45                                                   pat->pattern);
  46                else
  47                        append_grep_pattern(ret, pat->pattern, pat->origin,
  48                                            pat->no, pat->token);
  49        }
  50
  51        return ret;
  52}
  53
  54static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
  55{
  56        int err;
  57
  58        p->word_regexp = opt->word_regexp;
  59        p->ignore_case = opt->ignore_case;
  60        p->fixed = opt->fixed;
  61
  62        if (p->fixed)
  63                return;
  64
  65        err = regcomp(&p->regexp, p->pattern, opt->regflags);
  66        if (err) {
  67                char errbuf[1024];
  68                char where[1024];
  69                if (p->no)
  70                        sprintf(where, "In '%s' at %d, ",
  71                                p->origin, p->no);
  72                else if (p->origin)
  73                        sprintf(where, "%s, ", p->origin);
  74                else
  75                        where[0] = 0;
  76                regerror(err, &p->regexp, errbuf, 1024);
  77                regfree(&p->regexp);
  78                die("%s'%s': %s", where, p->pattern, errbuf);
  79        }
  80}
  81
  82static struct grep_expr *compile_pattern_or(struct grep_pat **);
  83static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  84{
  85        struct grep_pat *p;
  86        struct grep_expr *x;
  87
  88        p = *list;
  89        if (!p)
  90                return NULL;
  91        switch (p->token) {
  92        case GREP_PATTERN: /* atom */
  93        case GREP_PATTERN_HEAD:
  94        case GREP_PATTERN_BODY:
  95                x = xcalloc(1, sizeof (struct grep_expr));
  96                x->node = GREP_NODE_ATOM;
  97                x->u.atom = p;
  98                *list = p->next;
  99                return x;
 100        case GREP_OPEN_PAREN:
 101                *list = p->next;
 102                x = compile_pattern_or(list);
 103                if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 104                        die("unmatched parenthesis");
 105                *list = (*list)->next;
 106                return x;
 107        default:
 108                return NULL;
 109        }
 110}
 111
 112static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 113{
 114        struct grep_pat *p;
 115        struct grep_expr *x;
 116
 117        p = *list;
 118        if (!p)
 119                return NULL;
 120        switch (p->token) {
 121        case GREP_NOT:
 122                if (!p->next)
 123                        die("--not not followed by pattern expression");
 124                *list = p->next;
 125                x = xcalloc(1, sizeof (struct grep_expr));
 126                x->node = GREP_NODE_NOT;
 127                x->u.unary = compile_pattern_not(list);
 128                if (!x->u.unary)
 129                        die("--not followed by non pattern expression");
 130                return x;
 131        default:
 132                return compile_pattern_atom(list);
 133        }
 134}
 135
 136static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 137{
 138        struct grep_pat *p;
 139        struct grep_expr *x, *y, *z;
 140
 141        x = compile_pattern_not(list);
 142        p = *list;
 143        if (p && p->token == GREP_AND) {
 144                if (!p->next)
 145                        die("--and not followed by pattern expression");
 146                *list = p->next;
 147                y = compile_pattern_and(list);
 148                if (!y)
 149                        die("--and not followed by pattern expression");
 150                z = xcalloc(1, sizeof (struct grep_expr));
 151                z->node = GREP_NODE_AND;
 152                z->u.binary.left = x;
 153                z->u.binary.right = y;
 154                return z;
 155        }
 156        return x;
 157}
 158
 159static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 160{
 161        struct grep_pat *p;
 162        struct grep_expr *x, *y, *z;
 163
 164        x = compile_pattern_and(list);
 165        p = *list;
 166        if (x && p && p->token != GREP_CLOSE_PAREN) {
 167                y = compile_pattern_or(list);
 168                if (!y)
 169                        die("not a pattern expression %s", p->pattern);
 170                z = xcalloc(1, sizeof (struct grep_expr));
 171                z->node = GREP_NODE_OR;
 172                z->u.binary.left = x;
 173                z->u.binary.right = y;
 174                return z;
 175        }
 176        return x;
 177}
 178
 179static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 180{
 181        return compile_pattern_or(list);
 182}
 183
 184void compile_grep_patterns(struct grep_opt *opt)
 185{
 186        struct grep_pat *p;
 187        struct grep_expr *header_expr = NULL;
 188
 189        if (opt->header_list) {
 190                p = opt->header_list;
 191                header_expr = compile_pattern_expr(&p);
 192                if (p)
 193                        die("incomplete pattern expression: %s", p->pattern);
 194                for (p = opt->header_list; p; p = p->next) {
 195                        switch (p->token) {
 196                        case GREP_PATTERN: /* atom */
 197                        case GREP_PATTERN_HEAD:
 198                        case GREP_PATTERN_BODY:
 199                                compile_regexp(p, opt);
 200                                break;
 201                        default:
 202                                opt->extended = 1;
 203                                break;
 204                        }
 205                }
 206        }
 207
 208        for (p = opt->pattern_list; p; p = p->next) {
 209                switch (p->token) {
 210                case GREP_PATTERN: /* atom */
 211                case GREP_PATTERN_HEAD:
 212                case GREP_PATTERN_BODY:
 213                        compile_regexp(p, opt);
 214                        break;
 215                default:
 216                        opt->extended = 1;
 217                        break;
 218                }
 219        }
 220
 221        if (opt->all_match || header_expr)
 222                opt->extended = 1;
 223        else if (!opt->extended)
 224                return;
 225
 226        /* Then bundle them up in an expression.
 227         * A classic recursive descent parser would do.
 228         */
 229        p = opt->pattern_list;
 230        if (p)
 231                opt->pattern_expression = compile_pattern_expr(&p);
 232        if (p)
 233                die("incomplete pattern expression: %s", p->pattern);
 234
 235        if (!header_expr)
 236                return;
 237
 238        if (opt->pattern_expression) {
 239                struct grep_expr *z;
 240                z = xcalloc(1, sizeof(*z));
 241                z->node = GREP_NODE_OR;
 242                z->u.binary.left = opt->pattern_expression;
 243                z->u.binary.right = header_expr;
 244                opt->pattern_expression = z;
 245        } else {
 246                opt->pattern_expression = header_expr;
 247        }
 248        opt->all_match = 1;
 249}
 250
 251static void free_pattern_expr(struct grep_expr *x)
 252{
 253        switch (x->node) {
 254        case GREP_NODE_ATOM:
 255                break;
 256        case GREP_NODE_NOT:
 257                free_pattern_expr(x->u.unary);
 258                break;
 259        case GREP_NODE_AND:
 260        case GREP_NODE_OR:
 261                free_pattern_expr(x->u.binary.left);
 262                free_pattern_expr(x->u.binary.right);
 263                break;
 264        }
 265        free(x);
 266}
 267
 268void free_grep_patterns(struct grep_opt *opt)
 269{
 270        struct grep_pat *p, *n;
 271
 272        for (p = opt->pattern_list; p; p = n) {
 273                n = p->next;
 274                switch (p->token) {
 275                case GREP_PATTERN: /* atom */
 276                case GREP_PATTERN_HEAD:
 277                case GREP_PATTERN_BODY:
 278                        regfree(&p->regexp);
 279                        break;
 280                default:
 281                        break;
 282                }
 283                free(p);
 284        }
 285
 286        if (!opt->extended)
 287                return;
 288        free_pattern_expr(opt->pattern_expression);
 289}
 290
 291static char *end_of_line(char *cp, unsigned long *left)
 292{
 293        unsigned long l = *left;
 294        while (l && *cp != '\n') {
 295                l--;
 296                cp++;
 297        }
 298        *left = l;
 299        return cp;
 300}
 301
 302static int word_char(char ch)
 303{
 304        return isalnum(ch) || ch == '_';
 305}
 306
 307static void output_color(struct grep_opt *opt, const void *data, size_t size,
 308                         const char *color)
 309{
 310        if (opt->color && color && color[0]) {
 311                opt->output(opt, color, strlen(color));
 312                opt->output(opt, data, size);
 313                opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 314        } else
 315                opt->output(opt, data, size);
 316}
 317
 318static void output_sep(struct grep_opt *opt, char sign)
 319{
 320        if (opt->null_following_name)
 321                opt->output(opt, "\0", 1);
 322        else
 323                output_color(opt, &sign, 1, opt->color_sep);
 324}
 325
 326static void show_name(struct grep_opt *opt, const char *name)
 327{
 328        output_color(opt, name, strlen(name), opt->color_filename);
 329        opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 330}
 331
 332
 333static int fixmatch(const char *pattern, char *line, int ignore_case, regmatch_t *match)
 334{
 335        char *hit;
 336        if (ignore_case)
 337                hit = strcasestr(line, pattern);
 338        else
 339                hit = strstr(line, pattern);
 340
 341        if (!hit) {
 342                match->rm_so = match->rm_eo = -1;
 343                return REG_NOMATCH;
 344        }
 345        else {
 346                match->rm_so = hit - line;
 347                match->rm_eo = match->rm_so + strlen(pattern);
 348                return 0;
 349        }
 350}
 351
 352static int strip_timestamp(char *bol, char **eol_p)
 353{
 354        char *eol = *eol_p;
 355        int ch;
 356
 357        while (bol < --eol) {
 358                if (*eol != '>')
 359                        continue;
 360                *eol_p = ++eol;
 361                ch = *eol;
 362                *eol = '\0';
 363                return ch;
 364        }
 365        return 0;
 366}
 367
 368static struct {
 369        const char *field;
 370        size_t len;
 371} header_field[] = {
 372        { "author ", 7 },
 373        { "committer ", 10 },
 374};
 375
 376static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 377                             enum grep_context ctx,
 378                             regmatch_t *pmatch, int eflags)
 379{
 380        int hit = 0;
 381        int saved_ch = 0;
 382        const char *start = bol;
 383
 384        if ((p->token != GREP_PATTERN) &&
 385            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 386                return 0;
 387
 388        if (p->token == GREP_PATTERN_HEAD) {
 389                const char *field;
 390                size_t len;
 391                assert(p->field < ARRAY_SIZE(header_field));
 392                field = header_field[p->field].field;
 393                len = header_field[p->field].len;
 394                if (strncmp(bol, field, len))
 395                        return 0;
 396                bol += len;
 397                saved_ch = strip_timestamp(bol, &eol);
 398        }
 399
 400 again:
 401        if (p->fixed)
 402                hit = !fixmatch(p->pattern, bol, p->ignore_case, pmatch);
 403        else
 404                hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
 405
 406        if (hit && p->word_regexp) {
 407                if ((pmatch[0].rm_so < 0) ||
 408                    (eol - bol) < pmatch[0].rm_so ||
 409                    (pmatch[0].rm_eo < 0) ||
 410                    (eol - bol) < pmatch[0].rm_eo)
 411                        die("regexp returned nonsense");
 412
 413                /* Match beginning must be either beginning of the
 414                 * line, or at word boundary (i.e. the last char must
 415                 * not be a word char).  Similarly, match end must be
 416                 * either end of the line, or at word boundary
 417                 * (i.e. the next char must not be a word char).
 418                 */
 419                if ( ((pmatch[0].rm_so == 0) ||
 420                      !word_char(bol[pmatch[0].rm_so-1])) &&
 421                     ((pmatch[0].rm_eo == (eol-bol)) ||
 422                      !word_char(bol[pmatch[0].rm_eo])) )
 423                        ;
 424                else
 425                        hit = 0;
 426
 427                /* Words consist of at least one character. */
 428                if (pmatch->rm_so == pmatch->rm_eo)
 429                        hit = 0;
 430
 431                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 432                        /* There could be more than one match on the
 433                         * line, and the first match might not be
 434                         * strict word match.  But later ones could be!
 435                         * Forward to the next possible start, i.e. the
 436                         * next position following a non-word char.
 437                         */
 438                        bol = pmatch[0].rm_so + bol + 1;
 439                        while (word_char(bol[-1]) && bol < eol)
 440                                bol++;
 441                        eflags |= REG_NOTBOL;
 442                        if (bol < eol)
 443                                goto again;
 444                }
 445        }
 446        if (p->token == GREP_PATTERN_HEAD && saved_ch)
 447                *eol = saved_ch;
 448        if (hit) {
 449                pmatch[0].rm_so += bol - start;
 450                pmatch[0].rm_eo += bol - start;
 451        }
 452        return hit;
 453}
 454
 455static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 456                           enum grep_context ctx, int collect_hits)
 457{
 458        int h = 0;
 459        regmatch_t match;
 460
 461        if (!x)
 462                die("Not a valid grep expression");
 463        switch (x->node) {
 464        case GREP_NODE_ATOM:
 465                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 466                break;
 467        case GREP_NODE_NOT:
 468                h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 469                break;
 470        case GREP_NODE_AND:
 471                if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 472                        return 0;
 473                h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 474                break;
 475        case GREP_NODE_OR:
 476                if (!collect_hits)
 477                        return (match_expr_eval(x->u.binary.left,
 478                                                bol, eol, ctx, 0) ||
 479                                match_expr_eval(x->u.binary.right,
 480                                                bol, eol, ctx, 0));
 481                h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 482                x->u.binary.left->hit |= h;
 483                h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 484                break;
 485        default:
 486                die("Unexpected node type (internal error) %d", x->node);
 487        }
 488        if (collect_hits)
 489                x->hit |= h;
 490        return h;
 491}
 492
 493static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 494                      enum grep_context ctx, int collect_hits)
 495{
 496        struct grep_expr *x = opt->pattern_expression;
 497        return match_expr_eval(x, bol, eol, ctx, collect_hits);
 498}
 499
 500static int match_line(struct grep_opt *opt, char *bol, char *eol,
 501                      enum grep_context ctx, int collect_hits)
 502{
 503        struct grep_pat *p;
 504        regmatch_t match;
 505
 506        if (opt->extended)
 507                return match_expr(opt, bol, eol, ctx, collect_hits);
 508
 509        /* we do not call with collect_hits without being extended */
 510        for (p = opt->pattern_list; p; p = p->next) {
 511                if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 512                        return 1;
 513        }
 514        return 0;
 515}
 516
 517static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 518                              enum grep_context ctx,
 519                              regmatch_t *pmatch, int eflags)
 520{
 521        regmatch_t match;
 522
 523        if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 524                return 0;
 525        if (match.rm_so < 0 || match.rm_eo < 0)
 526                return 0;
 527        if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 528                if (match.rm_so > pmatch->rm_so)
 529                        return 1;
 530                if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 531                        return 1;
 532        }
 533        pmatch->rm_so = match.rm_so;
 534        pmatch->rm_eo = match.rm_eo;
 535        return 1;
 536}
 537
 538static int next_match(struct grep_opt *opt, char *bol, char *eol,
 539                      enum grep_context ctx, regmatch_t *pmatch, int eflags)
 540{
 541        struct grep_pat *p;
 542        int hit = 0;
 543
 544        pmatch->rm_so = pmatch->rm_eo = -1;
 545        if (bol < eol) {
 546                for (p = opt->pattern_list; p; p = p->next) {
 547                        switch (p->token) {
 548                        case GREP_PATTERN: /* atom */
 549                        case GREP_PATTERN_HEAD:
 550                        case GREP_PATTERN_BODY:
 551                                hit |= match_next_pattern(p, bol, eol, ctx,
 552                                                          pmatch, eflags);
 553                                break;
 554                        default:
 555                                break;
 556                        }
 557                }
 558        }
 559        return hit;
 560}
 561
 562static void show_line(struct grep_opt *opt, char *bol, char *eol,
 563                      const char *name, unsigned lno, char sign)
 564{
 565        int rest = eol - bol;
 566        char *line_color = NULL;
 567
 568        if (opt->pre_context || opt->post_context) {
 569                if (opt->last_shown == 0) {
 570                        if (opt->show_hunk_mark) {
 571                                output_color(opt, "--", 2, opt->color_sep);
 572                                opt->output(opt, "\n", 1);
 573                        }
 574                } else if (lno > opt->last_shown + 1) {
 575                        output_color(opt, "--", 2, opt->color_sep);
 576                        opt->output(opt, "\n", 1);
 577                }
 578        }
 579        opt->last_shown = lno;
 580
 581        if (opt->pathname) {
 582                output_color(opt, name, strlen(name), opt->color_filename);
 583                output_sep(opt, sign);
 584        }
 585        if (opt->linenum) {
 586                char buf[32];
 587                snprintf(buf, sizeof(buf), "%d", lno);
 588                output_color(opt, buf, strlen(buf), opt->color_lineno);
 589                output_sep(opt, sign);
 590        }
 591        if (opt->color) {
 592                regmatch_t match;
 593                enum grep_context ctx = GREP_CONTEXT_BODY;
 594                int ch = *eol;
 595                int eflags = 0;
 596
 597                if (sign == ':')
 598                        line_color = opt->color_selected;
 599                else if (sign == '-')
 600                        line_color = opt->color_context;
 601                else if (sign == '=')
 602                        line_color = opt->color_function;
 603                *eol = '\0';
 604                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 605                        if (match.rm_so == match.rm_eo)
 606                                break;
 607
 608                        output_color(opt, bol, match.rm_so, line_color);
 609                        output_color(opt, bol + match.rm_so,
 610                                     match.rm_eo - match.rm_so,
 611                                     opt->color_match);
 612                        bol += match.rm_eo;
 613                        rest -= match.rm_eo;
 614                        eflags = REG_NOTBOL;
 615                }
 616                *eol = ch;
 617        }
 618        output_color(opt, bol, rest, line_color);
 619        opt->output(opt, "\n", 1);
 620}
 621
 622static int match_funcname(struct grep_opt *opt, char *bol, char *eol)
 623{
 624        xdemitconf_t *xecfg = opt->priv;
 625        if (xecfg && xecfg->find_func) {
 626                char buf[1];
 627                return xecfg->find_func(bol, eol - bol, buf, 1,
 628                                        xecfg->find_func_priv) >= 0;
 629        }
 630
 631        if (bol == eol)
 632                return 0;
 633        if (isalpha(*bol) || *bol == '_' || *bol == '$')
 634                return 1;
 635        return 0;
 636}
 637
 638static void show_funcname_line(struct grep_opt *opt, const char *name,
 639                               char *buf, char *bol, unsigned lno)
 640{
 641        while (bol > buf) {
 642                char *eol = --bol;
 643
 644                while (bol > buf && bol[-1] != '\n')
 645                        bol--;
 646                lno--;
 647
 648                if (lno <= opt->last_shown)
 649                        break;
 650
 651                if (match_funcname(opt, bol, eol)) {
 652                        show_line(opt, bol, eol, name, lno, '=');
 653                        break;
 654                }
 655        }
 656}
 657
 658static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
 659                             char *bol, unsigned lno)
 660{
 661        unsigned cur = lno, from = 1, funcname_lno = 0;
 662        int funcname_needed = opt->funcname;
 663
 664        if (opt->pre_context < lno)
 665                from = lno - opt->pre_context;
 666        if (from <= opt->last_shown)
 667                from = opt->last_shown + 1;
 668
 669        /* Rewind. */
 670        while (bol > buf && cur > from) {
 671                char *eol = --bol;
 672
 673                while (bol > buf && bol[-1] != '\n')
 674                        bol--;
 675                cur--;
 676                if (funcname_needed && match_funcname(opt, bol, eol)) {
 677                        funcname_lno = cur;
 678                        funcname_needed = 0;
 679                }
 680        }
 681
 682        /* We need to look even further back to find a function signature. */
 683        if (opt->funcname && funcname_needed)
 684                show_funcname_line(opt, name, buf, bol, cur);
 685
 686        /* Back forward. */
 687        while (cur < lno) {
 688                char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 689
 690                while (*eol != '\n')
 691                        eol++;
 692                show_line(opt, bol, eol, name, cur, sign);
 693                bol = eol + 1;
 694                cur++;
 695        }
 696}
 697
 698static int should_lookahead(struct grep_opt *opt)
 699{
 700        struct grep_pat *p;
 701
 702        if (opt->extended)
 703                return 0; /* punt for too complex stuff */
 704        if (opt->invert)
 705                return 0;
 706        for (p = opt->pattern_list; p; p = p->next) {
 707                if (p->token != GREP_PATTERN)
 708                        return 0; /* punt for "header only" and stuff */
 709        }
 710        return 1;
 711}
 712
 713static int look_ahead(struct grep_opt *opt,
 714                      unsigned long *left_p,
 715                      unsigned *lno_p,
 716                      char **bol_p)
 717{
 718        unsigned lno = *lno_p;
 719        char *bol = *bol_p;
 720        struct grep_pat *p;
 721        char *sp, *last_bol;
 722        regoff_t earliest = -1;
 723
 724        for (p = opt->pattern_list; p; p = p->next) {
 725                int hit;
 726                regmatch_t m;
 727
 728                if (p->fixed)
 729                        hit = !fixmatch(p->pattern, bol, p->ignore_case, &m);
 730                else {
 731#ifdef REG_STARTEND
 732                        m.rm_so = 0;
 733                        m.rm_eo = *left_p;
 734                        hit = !regexec(&p->regexp, bol, 1, &m, REG_STARTEND);
 735#else
 736                        hit = !regexec(&p->regexp, bol, 1, &m, 0);
 737#endif
 738                }
 739                if (!hit || m.rm_so < 0 || m.rm_eo < 0)
 740                        continue;
 741                if (earliest < 0 || m.rm_so < earliest)
 742                        earliest = m.rm_so;
 743        }
 744
 745        if (earliest < 0) {
 746                *bol_p = bol + *left_p;
 747                *left_p = 0;
 748                return 1;
 749        }
 750        for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
 751                ; /* find the beginning of the line */
 752        last_bol = sp;
 753
 754        for (sp = bol; sp < last_bol; sp++) {
 755                if (*sp == '\n')
 756                        lno++;
 757        }
 758        *left_p -= last_bol - bol;
 759        *bol_p = last_bol;
 760        *lno_p = lno;
 761        return 0;
 762}
 763
 764int grep_threads_ok(const struct grep_opt *opt)
 765{
 766        /* If this condition is true, then we may use the attribute
 767         * machinery in grep_buffer_1. The attribute code is not
 768         * thread safe, so we disable the use of threads.
 769         */
 770        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 771            !opt->name_only)
 772                return 0;
 773
 774        return 1;
 775}
 776
 777static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 778{
 779        fwrite(buf, size, 1, stdout);
 780}
 781
 782static int grep_buffer_1(struct grep_opt *opt, const char *name,
 783                         char *buf, unsigned long size, int collect_hits)
 784{
 785        char *bol = buf;
 786        unsigned long left = size;
 787        unsigned lno = 1;
 788        unsigned last_hit = 0;
 789        int binary_match_only = 0;
 790        unsigned count = 0;
 791        int try_lookahead = 0;
 792        enum grep_context ctx = GREP_CONTEXT_HEAD;
 793        xdemitconf_t xecfg;
 794
 795        if (!opt->output)
 796                opt->output = std_output;
 797
 798        if (opt->last_shown && (opt->pre_context || opt->post_context) &&
 799            opt->output == std_output)
 800                opt->show_hunk_mark = 1;
 801        opt->last_shown = 0;
 802
 803        if (buffer_is_binary(buf, size)) {
 804                switch (opt->binary) {
 805                case GREP_BINARY_DEFAULT:
 806                        binary_match_only = 1;
 807                        break;
 808                case GREP_BINARY_NOMATCH:
 809                        return 0; /* Assume unmatch */
 810                        break;
 811                default:
 812                        break;
 813                }
 814        }
 815
 816        memset(&xecfg, 0, sizeof(xecfg));
 817        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 818            !opt->name_only && !binary_match_only && !collect_hits) {
 819                struct userdiff_driver *drv = userdiff_find_by_path(name);
 820                if (drv && drv->funcname.pattern) {
 821                        const struct userdiff_funcname *pe = &drv->funcname;
 822                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
 823                        opt->priv = &xecfg;
 824                }
 825        }
 826        try_lookahead = should_lookahead(opt);
 827
 828        while (left) {
 829                char *eol, ch;
 830                int hit;
 831
 832                /*
 833                 * look_ahead() skips quicly to the line that possibly
 834                 * has the next hit; don't call it if we need to do
 835                 * something more than just skipping the current line
 836                 * in response to an unmatch for the current line.  E.g.
 837                 * inside a post-context window, we will show the current
 838                 * line as a context around the previous hit when it
 839                 * doesn't hit.
 840                 */
 841                if (try_lookahead
 842                    && !(last_hit
 843                         && lno <= last_hit + opt->post_context)
 844                    && look_ahead(opt, &left, &lno, &bol))
 845                        break;
 846                eol = end_of_line(bol, &left);
 847                ch = *eol;
 848                *eol = 0;
 849
 850                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 851                        ctx = GREP_CONTEXT_BODY;
 852
 853                hit = match_line(opt, bol, eol, ctx, collect_hits);
 854                *eol = ch;
 855
 856                if (collect_hits)
 857                        goto next_line;
 858
 859                /* "grep -v -e foo -e bla" should list lines
 860                 * that do not have either, so inversion should
 861                 * be done outside.
 862                 */
 863                if (opt->invert)
 864                        hit = !hit;
 865                if (opt->unmatch_name_only) {
 866                        if (hit)
 867                                return 0;
 868                        goto next_line;
 869                }
 870                if (hit) {
 871                        count++;
 872                        if (opt->status_only)
 873                                return 1;
 874                        if (binary_match_only) {
 875                                opt->output(opt, "Binary file ", 12);
 876                                output_color(opt, name, strlen(name),
 877                                             opt->color_filename);
 878                                opt->output(opt, " matches\n", 9);
 879                                return 1;
 880                        }
 881                        if (opt->name_only) {
 882                                show_name(opt, name);
 883                                return 1;
 884                        }
 885                        /* Hit at this line.  If we haven't shown the
 886                         * pre-context lines, we would need to show them.
 887                         * When asked to do "count", this still show
 888                         * the context which is nonsense, but the user
 889                         * deserves to get that ;-).
 890                         */
 891                        if (opt->pre_context)
 892                                show_pre_context(opt, name, buf, bol, lno);
 893                        else if (opt->funcname)
 894                                show_funcname_line(opt, name, buf, bol, lno);
 895                        if (!opt->count)
 896                                show_line(opt, bol, eol, name, lno, ':');
 897                        last_hit = lno;
 898                }
 899                else if (last_hit &&
 900                         lno <= last_hit + opt->post_context) {
 901                        /* If the last hit is within the post context,
 902                         * we need to show this line.
 903                         */
 904                        show_line(opt, bol, eol, name, lno, '-');
 905                }
 906
 907        next_line:
 908                bol = eol + 1;
 909                if (!left)
 910                        break;
 911                left--;
 912                lno++;
 913        }
 914
 915        if (collect_hits)
 916                return 0;
 917
 918        if (opt->status_only)
 919                return 0;
 920        if (opt->unmatch_name_only) {
 921                /* We did not see any hit, so we want to show this */
 922                show_name(opt, name);
 923                return 1;
 924        }
 925
 926        xdiff_clear_find_func(&xecfg);
 927        opt->priv = NULL;
 928
 929        /* NEEDSWORK:
 930         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 931         * which feels mostly useless but sometimes useful.  Maybe
 932         * make it another option?  For now suppress them.
 933         */
 934        if (opt->count && count) {
 935                char buf[32];
 936                output_color(opt, name, strlen(name), opt->color_filename);
 937                output_sep(opt, ':');
 938                snprintf(buf, sizeof(buf), "%u\n", count);
 939                opt->output(opt, buf, strlen(buf));
 940        }
 941        return !!last_hit;
 942}
 943
 944static void clr_hit_marker(struct grep_expr *x)
 945{
 946        /* All-hit markers are meaningful only at the very top level
 947         * OR node.
 948         */
 949        while (1) {
 950                x->hit = 0;
 951                if (x->node != GREP_NODE_OR)
 952                        return;
 953                x->u.binary.left->hit = 0;
 954                x = x->u.binary.right;
 955        }
 956}
 957
 958static int chk_hit_marker(struct grep_expr *x)
 959{
 960        /* Top level nodes have hit markers.  See if they all are hits */
 961        while (1) {
 962                if (x->node != GREP_NODE_OR)
 963                        return x->hit;
 964                if (!x->u.binary.left->hit)
 965                        return 0;
 966                x = x->u.binary.right;
 967        }
 968}
 969
 970int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 971{
 972        /*
 973         * we do not have to do the two-pass grep when we do not check
 974         * buffer-wide "all-match".
 975         */
 976        if (!opt->all_match)
 977                return grep_buffer_1(opt, name, buf, size, 0);
 978
 979        /* Otherwise the toplevel "or" terms hit a bit differently.
 980         * We first clear hit markers from them.
 981         */
 982        clr_hit_marker(opt->pattern_expression);
 983        grep_buffer_1(opt, name, buf, size, 1);
 984
 985        if (!chk_hit_marker(opt->pattern_expression))
 986                return 0;
 987
 988        return grep_buffer_1(opt, name, buf, size, 0);
 989}